What is "lumpy jaw"

Actinomycosis \Ac`ti*no*my*co"sis\ ([a^]k`t[i^]*n[-o]*m[imac]*k[=o]"s[i^]s), n. [NL.] (Med.) A chronic infectious disease of cattle and man due to infection with actinomycetes, especially by Actinomyces bovis in cattle and by Actinomyces israeli or Arachnia propionica in man. It is characterized by hard swellings usually in the mouth and jaw. In man the disease may also affect the abdomen or thorax. Called also lumpy jaw or big jaw.

n. the commonest and least severe form of actinomycosis; affects the face and neck regions [syn: cervicofacial actinomycosis]